JPH10174837A - Harmful component removing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a catalyst amount of a combustion catalyst layer burning and removing a desorbed harmful component by discharging a waste gas passing an adsorbent layer to the atmosphere as it is, on the other hand, by introducing the adsorbent adsorbing the harmful component from an adsorbing vessel to a desorbing vessel and subjecting to a desorption by heating. SOLUTION: The waste gas 33 is flowed into the adsorbing vessel 1 through an inlet pipe 11 with a fan 5. The influent waste gas 33 is passed through the adsorbent 19 layer laminated on a funnel type grating 15 and the harmful component is adsorbed to the adsorbent 19. Then the purified waste gas 33 is discharged out of system through an outlet pipe 13 as a treated waste gas 35. The adsorbent 19 is supplied to an adsorbent residence part 21 of the desorbing vessel 3 through an adsorbent discharging pipe 17 and heated till a desorbing temp. with an incorporated heater 23. Then the harmful component is desorbed from the adsorbent 19. The desorbed harmful component is transported with the desorbed gas 37 and subjected to a combustion treatment at the combustion catalyst layer 25. The catalyst amount is reduced because the desorbed gas 37 amount and the adsorbent amount to be desorbed is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for removing harmful components contained in exhaust gas.

[0002]

2. Description of the Related Art Exhaust gas discharged from a reaction process of a chemical industry, exhaust gas discharged from a manufacturing process (firing, drying, washing) of resin, plywood, semiconductor, etc., or exhaust gas emitted from a paint baking drying process. Contains odor components and components harmful to the human body (hereinafter collectively referred to as harmful components as appropriate). For example, in the chemical industry, organic acids such as carbon monoxide, hydrocarbons, acetic acid and the like, aldehydes and the like are contained as cracking gases in raw materials and unyielded components. Further, from the manufacturing process and the coating process of the resin and the like, the exhaust gas contains alcoholic aromatic hydrocarbons such as toluene and acetone used as a solvent. In particular, some substances such as ammonia, amines, aldehydes, thiols, and the like show a strong odor only in a trace amount (ppm or less).

Therefore, if exhaust gas containing these components is exhausted to the atmosphere as it is, it emits offensive odor and is harmful to human beings. Therefore, from the viewpoint of pollution prevention, removal of harmful components which are deodorized and detoxified in advance before exhaustion. A device is provided.
Techniques for removing such harmful components are broadly classified into adsorption, absorption, combustion oxidation, and the like. Such a catalyst is widely used, and recently, a combustion oxidation method using a catalyst has been adopted because there is no reduction of auxiliary fuel or generation of NOx which causes secondary pollution.

[0004] As an example of a harmful component removing apparatus combining such an adsorption method and a catalytic combustion method, a layer filled with an adsorbent and a flow path through which a desorption heat medium flows are disposed so as to be able to exchange heat. Then, an ash gas containing a harmful component is passed through the adsorbent layer to adsorb and remove the harmful component, and the ash gas is sequentially passed through a heating means and a catalyst layer for combustion discharged from the adsorbent layer. An exhaust gas discharged from a catalyst layer for use is configured to be discharged into the atmosphere through the above-described flow path of the heat medium for desorption. Then, the above-mentioned heating means is normally stopped, and is operated when the adsorbent having adsorbed the harmful component is regenerated. That is, normally, the exhaust gas from which the harmful components are adsorbed and removed through the adsorbent layer is discharged to the atmosphere simply passing through the combustion catalyst layer and the flow path of the heat medium for desorption. On the other hand, in the case of regenerating the adsorbent, the exhaust gas discharged from the adsorbent layer is heated by the heating means, and is allowed to flow through the combustion catalyst layer into the flow path of the desorption heat medium. Hazardous components are desorbed from the adsorbent by heat. Due to this desorption, the heated exhaust gas discharged from the adsorbent layer contains harmful components, which are burned when passing through the combustion catalyst layer and are substantially removed from the exhaust gas. .

As the adsorbent, alumina, silica, silica-alumina, magnesia and other various clay minerals or zeolite are used, and those having a large specific surface area and a large adsorption capacity are used. As the combustion catalyst, a catalyst in which a noble metal such as platinum and palladium and a base metal such as manganese, iron, cobalt, and copper are supported on alumina is used.

[0006]

According to the above prior art, an exhaust gas containing a harmful component to be adsorbed in a desorption process is used as a carrier gas (desorption gas) for the harmful component desorbed as it is, and is used for combustion. Since the combustion treatment is performed by flowing through the catalyst layer, the amount of catalyst is required in proportion to the amount of exhaust gas, and the amount of catalyst becomes enormous.

An object of the present invention is to reduce the amount of a catalyst in a combustion catalyst layer for desorbing harmful components in exhaust gas after adsorbing the harmful components to an adsorbent and burning off the desorbed harmful components.

[0008]

Means for Solving the Problems To solve the above-mentioned problems, an adsorption vessel containing an adsorbent layer and a desorption vessel having an adsorbent retention section are provided. An exhaust gas line to be supplied to the adsorbent container and the desorption container are provided with a means for extracting the adsorbent to the adsorbent storage section, and the desorption container further includes a pipe for supplying desorbed gas to the adsorbent storage section; It is configured to include a means for heating the adsorbent in the adsorbent retaining section and a combustion catalyst layer for burning gas discharged from the adsorbent retaining section.

With this configuration, the adsorbent that has adsorbed harmful components in the adsorption vessel is discharged to the adsorbent retaining section of the desorption vessel, and is heated to a temperature suitable for desorption under the flow of desorption gas. You. The harmful components desorbed by this heating are conveyed to the desorbed gas and guided to the combustion catalyst layer, where they are burned and removed. In other words, while the exhaust gas flowing through the adsorbent layer is discharged to the atmosphere as it is, the adsorbent that has adsorbed the harmful components is extracted from the adsorption container, guided to the desorption container, and heated and desorbed in the desorption container. Instead of using the entire amount of exhaust gas, the components are transported by a desorbed gas in a separate flow path, guided to the catalyst layer, and subjected to combustion processing. Here, the gas required for desorption is generally small,
Since the amount of desorbed gas containing harmful components to be treated in the combustion catalyst layer can be reduced, the amount of catalyst can be reduced. Further, since the adsorbent is extracted and subjected to the desorption treatment, the amount of the adsorbent to be desorbed can be reduced, and from this point, the amount of the desorbed gas can be reduced and the catalyst amount can be reduced.

Further, the adsorbent layer built in the adsorption container is formed by retaining the adsorbent on a mesh-shaped funnel that allows exhaust gas to pass through, and the adsorbent is drawn out at the lower end of the funnel. It is desirable to connect a pipe line and withdraw the adsorbent to the adsorbent storage section of the desorption container, and to transport the desorbent discharged to the adsorbent storage section by a bucket elevator and return it to the adsorbent layer of the adsorption container. Thereby, the harmful component adsorption process and the desorption process can be performed continuously.

Further, exhaust gas can be used as the desorbing gas. In this case, it can be realized by providing a pipe connecting the adsorption vessel and the adsorbent retaining portion of the desorption vessel. According to this, it is not necessary to separately provide a means for supplying the desorbed gas, the structure can be simplified, and the cost can be reduced accordingly.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a harmful component removing apparatus of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an embodiment of a harmful component removing apparatus to which the present invention is applied. As shown in FIG. 1, the harmful component removing device includes an adsorption container 1, a desorption container 3, a fan 5, and a plurality of pipes 7 and 9.

In the adsorption vessel 1, an inlet pipe 11 for the exhaust gas 33 is provided at the lower part of the cylindrical vessel 10, and an outlet pipe 13 for the exhaust gas 33 is provided at the upper part. The outlet pipe 13 is connected to a chimney (not shown). I have. An adsorbent layer 14 is built in substantially the center of the interior of the adsorption container 1. The adsorbent layer 14 has a structure in which an adsorbent 19 is deposited on an upper part of a funnel 15. The funnel-shaped dish 15 is formed by fixing the top of a conical or pyramid-shaped pyramid downward, and fixing the bottom to the inner wall of the adsorption vessel 1 without any gap, and the side face is formed in a mesh shape so that exhaust gas can flow. I have. An opening is provided at the lowermost portion of the funnel-shaped dish 15, and the adsorbent discharge pipe 17 is provided in this opening.
The other end of the adsorbent discharge pipe 17 is connected to the desorption container 3. The cross section of the adsorption container 1 may be circular or rectangular. The adsorbent 19
Is desirably an adsorption-concentrated inorganic particulate material having heat resistance, for example, alumina, silica, silica-alumina, magnesia, other various clay minerals, or zeolite.

The desorption container 3 is formed by disposing an adsorbent retaining portion 21 at a lower portion of a cylindrical container 20 and a bucket elevator 29 at an upper portion thereof. The gap between the detachable container 3 and the bucket 27 has a tight structure. In addition, a mesh-shaped perforated plate through which exhaust gas can flow is provided on the bottom surface of the adsorbent retaining section 21, and a heater 23 is provided below the meshed perforated plate. Further, a combustion catalyst layer 25 is provided below the adsorbent retaining section 21. Bucket elevator 29
An endless belt 3 is attached to a pair of upper and lower rotating shafts 31.
A plurality of buckets 27 are fixed to the belt 30 by winding 0 around the belt 30. The bucket 27 is movable by rotating the belt 30 in the illustrated rotation direction.

An adsorbent discharge pipe 9 is connected between the uppermost part of the desorption container 3 and the adsorption container 1. The adsorbent discharge pipe 9 is connected above the installation location of the funnel type dish 15. Further, an exhaust gas supply pipe 7 is connected between the adsorption container 1 and the adsorbent retaining section 21.

Next, the operation will be described in detail. The exhaust gas 33 is guided by the fan 5 and flows into the adsorption vessel 1 through the inlet pipe 11. Then, the exhaust gas 33 flowing into the adsorption vessel 1 passes through the adsorbent 19 layer laminated on the funnel type dish 15. During this passage, the harmful components are adsorbed by the adsorbent 19 and concentrated. Then, the purified exhaust gas 33 is discharged outside the system as the treated exhaust gas 35 through the outlet pipe 13.

The adsorbent 19 is supplied to the adsorbent retaining section 21 provided in the desorption container 3 through the adsorbent discharge pipe 17. Here, the adsorbent 19 supplied to the adsorbent retaining section 21
Are favored in a saturated state, that is, a state in which harmful components can no longer be adsorbed. Then, the adsorbent 19 supplied to the adsorbent retaining section 21 is heated by the built-in heater 23 to a temperature suitable for desorption of the harmful component, whereby the harmful substance which has been concentrated from the adsorbent 19 is condensed. The components are desorbed. Then, the desorbed harmful components are guided to the combustion catalyst layer 25 together with the untreated exhaust gas 37 supplied from the exhaust gas supply pipe 7, where they are burned and removed at a low temperature by the oxidizing action of the catalyst. As a result, the purified exhaust gas is discharged out of the system as a combustion exhaust gas 39.

Next, the adsorbent 19 that has desorbed and regenerated the harmful components is pumped up by the bucket 27 in the adsorbent retaining section 21 and transported to the top of the desorption container 3 by the bucket elevator 29. Then, the adsorbent 19 is supplied to the funnel type dish 15 through the adsorbent discharge pipe 9 and again adsorbs harmful components of the exhaust gas 33. Thus, the adsorbent 19
The adsorption process and the desorption process are repeatedly performed.

According to the embodiment shown in FIG. 1, the exhaust gas 35 flowing through the adsorbent layer 14 is discharged to the atmosphere as it is, while the adsorbent 19 having adsorbed harmful components is withdrawn from the adsorption vessel 1 and desorbed. 3 and heat desorption in the desorption container 3. The harmful components desorbed at this time are not used for the entire amount of the exhaust gas 33, and the desorbed gas 3
7, the catalyst is conveyed to the catalyst layer 25 for combustion treatment, and the amount of desorbed gas 37 containing harmful components to be treated in the combustion catalyst layer 25 is reduced. Can be planned. In addition, since the adsorbent 19 is extracted and desorbed, the amount of adsorbent to be desorbed can be reduced, and the amount of catalyst can be reduced.

Further, since the adsorbent discharge pipe 17 is provided between the lowermost part of the funnel type dish 15 and the adsorbent retaining section 21 and the bucket elevator 29 is provided, the adsorbent 19 can be circulated. In addition, the removal of the harmful components and the desorption / regeneration treatment of the adsorbent 19 can be performed simultaneously and continuously. Further, it is desirable that the desorption / regeneration process of the adsorbent 19 approaches a saturated state.

Further, between the adsorption vessel 1 and the desorption vessel 3,
Since the exhaust gas supply pipe 7 is provided, the untreated exhaust gas 37 can be used as a desorbed gas. Thus, for example, there is no need to provide a means for supplying air from the outside as the desorbed gas. Further, simplification of the structure can be expected along with this, so that cost can be reduced.

Although the untreated exhaust gas 37 is used as a means for guiding the harmful components desorbed from the adsorbent 19 in the adsorbent retaining section 21 to the combustion catalyst layer 25, the present invention is not limited to this. It is also possible to use the combustion exhaust gas 39 or to take in air from outside with an air fan or the like. Although the heater 23 is provided downstream of the adsorbent retaining section 21 to heat only the adsorbent, the heater 23 may be provided in the exhaust gas supply pipe 7 to heat the untreated exhaust gas 37, for example.

[0023]

According to the harmful component removing apparatus of the present invention, the amount of desorbed gas to be treated in the combustion catalyst layer can be reduced because the amount of gas required for desorption is small. The amount can be reduced.

[Brief description of the drawings]

FIG. 1 is a process explanatory view showing an embodiment of a harmful component removing apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Adsorption container 3 Desorption container 7 Exhaust gas supply pipe 9 Adsorbent discharge pipe 15 Funnel type dish 17 Adsorbent extraction pipe 19 Adsorbent 21 Adsorbent retention part 25 Catalyst layer for combustion 29 Bucket elevator

Claims (4)

[Claims] 1. An adsorption container having a built-in adsorbent layer, a desorption container having an adsorbent retention section, an exhaust gas line for supplying exhaust gas containing harmful components to the adsorption container, and an adsorbent of the adsorption container. Adsorbent extracting means for extracting to the adsorbent retaining section,
A desorbing gas pipe for supplying a desorbing gas to the adsorbent retaining section, and a heating unit for heating the adsorbent in the adsorbent retaining section,
A harmful component removing device comprising: a combustion catalyst layer for burning desorbed gas discharged from the adsorbent retaining section. 2. The adsorbent layer contained in the adsorption container according to claim 1, wherein the adsorbent is formed on a mesh-shaped funnel that allows exhaust gas to pass therethrough, and the adsorbent layer is formed. The adsorbent discharge pipe is connected to the lower end of the adsorbent, and the desorbing agent discharged to the adsorbent retaining section is transported by a bucket elevator and supplied to the adsorption container. apparatus. 3. The harmful component removal method according to claim 1, wherein the desorbed gas is the exhaust gas, and the desorbed gas line is a line communicating the adsorption container and the desorption container. apparatus. 4. A harmful component contained in an exhaust gas is adsorbed on an adsorbent, and a high-temperature desorbing gas is passed through the adsorbent to desorb the harmful component. The desorbed gas containing the harmful component is catalytically burned. A harmful component removal method for removing harmful components, wherein the sorbent adsorbing the harmful components is extracted to another container, and a high-temperature desorbing gas is passed through the adsorbent to desorb the harmful components. .